Internal combustion engines, including diesel engines, gasoline engines, gaseous fuel-powered engines, and other engines known in the art may exhaust a complex mixture of air pollutants. The air pollutants may be composed of gaseous compounds such as nitrogen oxides and carbon monoxide, and solid particulate matter, which may include unburned carbon particles also known as soot.
Due to increased awareness of the environment, exhaust emission standards have become more stringent, and the amount of gaseous compounds and particulate matter emitted from an engine may be regulated depending on the type of engine, size of engine, and/or class of engine. One method that has been implemented by engine manufacturers to comply with the regulation of emissions has been to remove the gaseous compounds and particulate matter from the exhaust flow of an engine using an exhaust treatment device. An exhaust treatment device typically includes a filter medium designed to trap particulate matter, and a catalyst utilized to absorb or convert the nitrogen oxides and/or carbon monoxide to inert fluids.
However, the use of the exhaust treatment device for extended periods of time can cause particulate matter to build up in the filter medium, thereby reducing the functionality of the filter and subsequently engine performance. The collected particulate matter may be removed from the filter through a process called regeneration. To initiate regeneration of the filter, the temperature of the particulate matter entrained within the filter must be elevated above a combustion threshold, at which the particulate matter is burned away. One way to elevate the temperature of the particulate matter is to inject fuel into the exhaust flow of the engine and ignite the injected fuel. The heat resulting from this fuel combustion, in addition to regenerating the filtration medium, may also or alternatively be selectively directed to the catalyst to improve operation of the device.
One way to enhance the efficiency of this heating process is to mix the injected fuel with air prior to and/or during combustion. That is, a homogenous air/fuel mixture, when ignited, may produce an evenly distributed flame that efficiently burns away the particulate matter from the filtration medium and/or heats the catalytic device. To control this mixing and heating process, it may be important to detect ignition of the mixture and/or the temperature of the mixture as the process progresses.
An example of injecting fuel and igniting the injected fuel to regenerate a particulate filter is described in U.S. Pat. No. 4,987,738 (the '738 patent) issued to Lopez-Crevillen et al. on Jan. 29, 1991. Specifically, the '738 patent discloses a canister having a particulate filter disposed therein. A diffuser connects the canister to a mixing chamber, which is in turn connected to a burner. A fuel injector nozzle is mounted within the burner for injecting fuel into the mixing chamber during regeneration. As the fuel, under pressure, is injected by the nozzle into the mixing chamber, high pressure air is also directed through the burner and mixing chamber to atomize the fuel. An igniter also mounted within the burner is then energized to ignite the atomized air-fuel mixture, and the burning mixture is combined with metered exhaust gas and directed through the diffuser to the canister. This heated fuel-air-exhaust mixture is then used to incinerate trapped particulates.
Although the burner configuration of the '738 patent may suitably regenerate a particulate-laden filter, it may be large, and inefficient. Specifically, because the mixing chamber is separate from the burner apparatus and sequentially located with respect to flow through the burner apparatus, it may consume valuable space within an engine compartment or undercarriage of a vehicle. Further, the burner configuration of the '738 patent may provide no way to detect ignition of the fuel-air mixture or temperature of the combustion process. Without a way to confirm ignition, flame extinction, or monitor the combustion process, the process could progress inefficiently or not at all, with no indication of its poor performance being communicated, observed, or accommodated.
The fuel burner of the present disclosure solves one or more of the problems set forth above.